The challenges associated with water and soil contamination is becoming an issue of global concern, these challenges are attributed to concentrated urban, industrial, and agricultural activities necessitating for sustainable and innovative remediation solutions. This article provides an all-inclusive review of three-dimensional polysaccharide-based hydrogels (PBH), as a novel remediation class of biomaterial matrix. PBH are derived from polymers which are biodegradable, abundant, and renewable, some of which are alginate, chitosan, and cellulose which provides an alternative to those used conventionally which are in comparison, not ecofriendly, costly, and whose method of treatment is detrimental. A critical review was provided by this article on the PBH synthesis methods, which includes the chemical and physical crosslinking methods, which have been found to be critical in streamlining their physicochemical characteristics such as mechanical stability, swelling capacity, and porosity. The various applications of PBH were also presented in this study, with a major focus on water remediation, specifically on heavy metal ions, antibiotics, organic dyes removal, and other notable emerging pollutants, the roles played by PBHs in treatment of soil such as in serving as carriers in agrochemical release which are regulated, conditioning of soil for retention of water, and materials for the containment of pollutants fixed in soil. Although polysaccharide hydrogels demonstrate significant promise, there exist profound issues regarding their mechanical strength in various real-world environments, their long term-stability, and production scale-up. A focus on the development of smart and advanced multifunctional hydrogel composites that incorporates stimuli-responsive behaviours with enhanced durability, creating avenues for the next generation, sustainable technologies that adhere to the principles of a circular economy are the future research efforts.